In the current market, there are the conventional percussion drillers with three modes of working, which are electrical screwdriver, electric driller and percussion driller. Three working modes correspond to three function gears, which adjusts the output torque force and the toggle between different function gears. This kind of percussion driller includes the front cover of gearbox, torsion cup, output main shaft, and the upper ratchet wheel, bottom ratchet wheel, ring gear, gear set and motor that connects with the output main shaft. The torsion cup connects with the screw threads on the upper end of the gear box front cover by adjusting the net. The bottom ratchet wheel joggles with the upper ratchet wheel. There is the trip stop gasket underneath the adjustment screw and the compression spring located between the trip stop gasket and the adjustment screw. There are the steel balls between the ring gear and trip stop gasket. When the torsion cup is being turned around, the torsion cup and adjustment screw will press on the compression spring, trip stop gasket and steel balls, thus adjusting the output torque force. When it is toggled to the percussion gear, the upper ratchet wheel causes the percussion space between two ratchet wheels. The output main shaft conducts alternate motion in axial direction by the interactive forces of the upper ratchet wheel and the bottom ratchet wheel, thus realizing the percussion function.
This percussion driller often sets the percussion gear where the torsion cup is in the maximum torque gear. However, out of the considerations of safety, the percussion products out there in the market need to switch to the minimum torque force gear. When using the percussion driller, the user often needs to switch between minimum torque gear and the percussion gear. Every time the toggle angle the user turns is large and the toggle can only be carried out when the motor ceases working. It is inconvenient, unsafe and low in efficiency.